Filter assembly

ABSTRACT

A filter assembly for a household water filtration apparatus, and a method for filtering water using a household water filtration apparatus are provided. The filter assembly comprises a through-flow cartridge, which has an accessible cavity. The cartridge is removably received in the household water filtration apparatus. The filter assembly further comprises a water permeable enclosure that contains filter media, which is removably received in the accessible cavity. The method comprises opening a through-flow cartridge, depositing a filter packet in the cartridge, closing the cartridge, depositing the cartridge in the household water filtration apparatus, and passing water through the cartridge. Alternately, the filter assembly may be fabricated using polylactic acid.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.12/194,036 (now allowed), which is a continuation-in-part of U.S. patentapplication Ser. No. 11/960,018 (now abandoned), which claims priorityto Provisional Application No. 61/007,899 (filed on Aug. 29, 2007), eachof which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The invention relates to filter assemblies for a portable waterfiltration apparatus. More specifically, the invention relates to filterassemblies that are environmentally friendly.

BACKGROUND OF THE INVENTION

Portable water filtration apparatus, such as those sold under the Britatrade mark, include countertop water filters and faucet mounted waterfilters. These water filters typically include a filter assembly thatincludes a filtration media, such as activated carbon. These filterassemblies are fitted into the water filters. For example, a filterassembly may be fitted onto or into a funnel member coupled to areceiving container (a water reservoir) for collecting liquid, or onto afixture coupled to a faucet wherein the water from the faucet flowsthrough the fixture prior to being dispensed.

Known filter assemblies generally include a cartridge which housesgranulated carbon. For example, U.S. Pat. Nos. 6,012,232 to Weyrauch and6,099,728 to Bairischer describe a cartridge in the form of a closedcup, which has holes on the upper and lower portions through which waterpasses as it is filtered. The cup houses granulated carbon, and theholes on the upper and lower portions are covered with a sieve cloth toprevent the granulated carbon from escaping. Over time, the granulatedcarbon in such cartridges becomes spent, and the user must dispose ofthe cartridge and replace it with a new one.

SUMMARY OF THE INVENTION

In accordance with this invention, filter assemblies that areenvironmentally friendly are provided. Various embodiments are providedthat may be used individually or in combination. Accordingly, a filtercartridge that is openable to receive a water-permeable enclosure thathouses filter media, preferably lose granular filter material, isprovided. Alternately, or in addition, a filter enclosure, or partthereof, that is made of polylactic acid, is provided.

Accordingly, in one broad aspect, the present invention provides afilter assembly for a portable water filtration apparatus. The filterassembly comprises a through-flow cartridge, wherein the cartridge hasan accessible cavity. A water permeable enclosure is removably receivedin the accessible cavity. The cavity may be openable (such as by thecartridge having a moveable or removable lid) or the cartridge may beprovided with an access slot though which a cartridge may be inserted.The permeable enclosure houses a filtration media. Preferably, thefilter assembly is removably received in the water filtration apparatus.However, in an alternate embodiment, the cavity may be opened while thefilter assembly is positioned in the water filtration apparatus. Thefilter media is preferably lose granular material, such as may be usedto filter water which passes through the filter material due to gravity.

In another broad aspect, the present invention provides a method forfiltering water using a water filter apparatus. The method comprisesopening a through-flow cartridge, depositing a filter packet in thecartridge, closing the cartridge, depositing the cartridge in theportable water filtration apparatus, and passing water through thecartridge.

An advantage of these broad aspects is that as the filtration mediabecomes spent, the permeable enclosure may be removed from the cartridgeand replaced, without requiring the replacement of the entire cartridge.The cartridge is typically comprised of plastic. Plastic is typicallynot biodegradable and will remain in landfill for an extended period oftime. By replacing the filter media and reusing the cartridge, theamount of waste that is sent to landfills is reduced. Further, much orsubstantially all of the waste that is sent to land fill, namely thefilter media, may be a natural source material, e.g., carbon and mineralstone.

A further advantage of the present invention is that the space requiredto store replacement permeable enclosures is less then the spacerequired to store replacement cartridges. The components of areplacement cartridges are relatively inexpensive. However, the volumeoccupied by them has a substantial impact on the cost of shipping andwarehousing the product. Accordingly, by providing replacement permeableenclosures, costs and storage space may be reduced.

In accordance with this aspect of the present invention, there isprovided a filter assembly for a household water filtration apparatus,the filter assembly comprising:

-   -   (a) a through-flow cartridge having an accessible cavity,        wherein the cartridge is received in the household water        filtration apparatus;    -   (b) a water-permeable enclosure removably receivable in the        accessible cavity; and,    -   (c) the permeable enclosure housing filtration media.

In some embodiments, the through-flow cartridge is removably received inthe household water filtration apparatus. In other embodiments, aportion of the through-flow cartridge is permanently secured to thehousehold water filtration apparatus.

In some embodiments, the through flow cartridge is positioned in agravity fed water flow passage from a feed water reservoir to a filteredwater reservoir of the household water filtration apparatus.

In one embodiment, the through-flow cartridge comprises a cup having anopenable lid. Preferably, the cup and the lid have mating screw threads.However, they may be moveably connected to each other by any means so asto permit access to the cavity. In some embodiments, the openable lid isaccessible when a lid of the household water filtration apparatus isopened.

In another embodiment, the permeable enclosure comprises a mesh.Preferably, the mesh is non-woven. The mesh may comprise hydrophobicfilaments. The mesh may be a plastic and, preferably, comprises at leastone of polypropylene and nylon.

In another embodiment, the permeable enclosure has a longitudinallyextending sidewall, a water permeable top, and a water permeable bottom.Preferably, the longitudinally extending sidewall is impermeable towater and the water permeable top and a water permeable bottom comprisea mesh. Preferably, the longitudinally extending sidewall is rigid.

In another embodiment, the permeable enclosure is without a fixed shape.

In another embodiment, the through-flow cartridge comprises a lowerportion having apertures and an upper portion having apertures and thefilter assembly further comprises at least one support structure thatpositions the permeable enclosure within the cavity and spaced from atleast the lower apertures. Preferably, the at least one supportstructure retains the permeable enclosure spaced from the apertures ofthe lower portion and the upper portion. Accordingly, there may be anupper and a lower support structure.

In another embodiment, the at least one support structure is removablefrom the cartridge. Alternately, they may be formed as part of thecartridge.

In another embodiment, the support structures comprise an open web disc.

In another embodiment, the filtration media comprises at least onemember selected from the group carbon, mineral stone and ceramic. Thefilter material may be any of those known in the art for gravity fedwater filters.

In another embodiment, the household water filtration apparatus furthercomprises a filtered water reservoir that is less than 5L in volume.

In another embodiment, the household water filtration apparatuscomprises a container that is fabricated from glass.

Preferably, the water filtration apparatus is a portable waterfiltration apparatus and, more preferably, a countertop water filtrationapparatus.

In accordance with another aspect of the present invention, there isprovided a method for filtering water using a household water filtrationapparatus, the method comprising:

-   -   (a) opening a through-flow cartridge;    -   (b) depositing a filter packet in the cartridge;    -   (c) closing the cartridge;    -   (d) depositing the cartridge in the household water filtration        apparatus; and,    -   (e) passing water through the cartridge.

In one embodiment, the method further comprises removing the filterpacket from the cartridge, and depositing another filter packet in thecartridge.

In another embodiment, the method further comprises placing a firstsupport structure in the cartridge, below the filter packet.

In another embodiment, the through-flow cartridge comprises a lowerportion having apertures, and the method further comprising retainingthe filter packet spaced from the apertures of the lower portion.Preferably, the method further comprises placing another supportstructure in the cartridge, above the filter packet. In such anembodiment, the through-flow cartridge comprises an upper portion havingapertures, and the method further comprises retaining the filter packetspaced from the apertures of the upper portion.

In another embodiment, the household water filtration apparatus isportable and the method further comprises transporting the householdwater filtration apparatus to a faucet to add water to a feed waterreservoir.

In another embodiment, the method further comprises providing a waterfiltration apparatus with a filtered water reservoir having a volume ofless than 5L.

In another embodiment, the method further comprises opening a lid of thewater filtration apparatus and subsequently opening a lid of thethrough-flow cartridge. For example, the through-flow cartridge may beremoved from the water filtration apparatus prior to opening the lid ofthe through-flow cartridge. Alternately, the lid of the through-flowcartridge may be opened while the through-flow cartridge is positionedin the water filtration apparatus.

In another embodiment, the method further comprises simultaneouslyopening a lid of the water filtration apparatus and opening a lid of thethrough-flow cartridge.

In accordance with another broad aspect, the present invention providesa filter assembly for a household water filtration apparatus, the filterassembly comprising:

-   -   (a) a through-flow cartridge defining a cavity    -   (b) a water-permeable enclosure receivable in the cavity and        housing filtration media; and,    -   (c) the water-permeable enclosure and the through-flow cartridge        are configured to direct water into the water-permeable        enclosure.

An advantage of this broad aspect is that the water entering the filterassembly is substantially prevented from bypassing the enclosure.Accordingly, most or all of the water is directed into the enclosure,and contacts the filtration media. Accordingly, most or all of the wateris subjected to filtration.

In some embodiments, the through-flow cartridge is openable to accessthe cavity. For example, the cartridge may comprise a cup and anopenable lid.

In some embodiments, the filter assembly comprises an annular gapbetween the cup and the water-permeable enclosure, and thewater-permeable enclosure engages the through-flow cartridge to inhibitflow of water through the annular gap.

In some embodiments, the through flow cartridge comprises a cup and alid, and the through-flow cartrdrige comprises at least one seatingsurface extending from the cup around an outer portion of the cavity,and the lid has an engagement surface that is positioned above theseating surface when the lid is in a closed position. Thewater-permeable enclosure comprises a flange extending from an upperportion of the water-permeable enclosure. The flange is securablebetween the seating surface and the engagement surface when the lid isin the closed position.

In some embodiments, the permeable enclosure comprises a waterimpermeable longitudinally extending sidewall, a water permeable top,and a water permeable bottom. In some such embodiments, at least one ofthe longitudinally extending sidewall, water permeable top, and waterpermeable bottom are fabricated from polylactic acid.

In some embodiments, the cup and the lid comprise mating screw threads,and the flange is held between the engagement surface and the seatingsurface when the lid and the cup are screwed together.

In some embodiments, the engagement surface, flange, and seating surfaceform a water impermeable seal.

In some embodiments, the through-flow cartridge is removably received inthe household water filtration apparatus.

In accordance with another broad aspect, a filter assembly for a waterfiltration apparatus is provided wherein at least a portion of thecontainer that houses the filter media is fabricated from polylacticacid.

Embodiments in accordance with this broad aspect may be advantageousbecause the container may be biodegradable. Accordingly, rather thandiscarding the container, the container may be composted. Surprisingly,it has been determined that despite deteriorating when in contact withwater, such a container may have a sufficient shelf life to provide acommercial product. Typically, filter media is damp when shipped.Therefore, the container will be in contact with water during packaging,shipment, storage and use. Despite this, if the container is generallyhoused in a cold environment, such as a refrigerator, the shelf life ofthe container may be roughly equal to (or greater than) the filtrationcapacity of the filtration media. Accordingly, the container may bebiodegradable without reducing the shelf life of the filter assembly.

In accordance with this aspect of the present invention, there isprovided a filter assembly for a water filtration apparatus, the filterassembly comprising at least one container housing filtration mediawherein at least a portion of the container is fabricated frompolylactic acid.

In some embodiments, the container is received in a filter cartridge.

In some embodiments, the filter cartridge comprises an accessible cavityand the container is removably received in the cavity.

In some embodiments, the container comprises a through-flow cartridge.For example, the container may comprise a water impermeablelongitudinally extending sidewall, a water permeable top, and a waterpermeable bottom and the sidewall is fabricated from polylactic acid

In some embodiments, the filtration media directly contacts thecontainer.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other advantages of the present invention will be more fullyand particularly understood in connection with the following descriptionof the preferred embodiments of the invention in which:

FIG. 1 is a front elevation view of a portable water treatment apparatusincluding a filter assembly as is known in the art;

FIG. 2 is a perspective drawing of an embodiment of a filter assembly ofthe present invention;

FIG. 3 is an exploded view of the filter assembly of FIG. 2;

FIG. 4 is a partial longitudinal cross-section along the line 4-4 of theembodiment of FIG. 2;

FIG. 5 is an enlarged cross-section of area A of FIG. 4;

FIG. 6 is an enlarged cross-section of area B of FIG. 4;

FIG. 7 is a partial longitudinal cross-section along line 4-4 of theembodiment of FIG. 2, shown together with a portable water treatmentapparatus;

FIG. 8 is a partial longitudinal cross-section along line 4-4 of analternate embodiment of FIG. 2 wherein a portion of the cartridge issecured to the water treatment apparatus, shown together with a portablewater treatment apparatus, with a lid of a cartridge opened, and with apermeable enclosure partially removed from the cartridge;

FIG. 9A is a perspective drawing of an alternate embodiment of a filterassembly of the present invention;

FIG. 9B is a cross section taken along line B-B in FIG. 9A; and,

FIG. 9C is an enlarged drawing of the region shown in box C in FIG. 9B.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIG. 1, a household water treatment apparatus 10 comprises acontainer 12 having a filtered water reservoir 14, an optional handle 16and an optional pour spout 18. The volume of filtered water reservoirmay be 0.5-5 liters, and preferably less than 2 litres. Accordingly,household water treatment apparatus 10 may be easily carried by a userby means of handle 16 and accordingly is typically used in householdenvironments. In such an embodiment, household water treatment apparatus10 comprises a portable water treatment apparatus. Such a portable watertreatment apparatus 10 may be stored on a counter top in a kitchen or ina refrigerator. Portable water treatment apparatus 10 is also providedwith an upper portion that defines a feed water reservoir 22. The feedwater reservoir may be filed with water that is to be treated by beingpassed, due to gravity, through filter assembly 28. Filter assembly 28is removably receivable in household water treatment apparatus 10, suchas by being slideable receivable in filter assembly holder 24. Filterassembly holder has an open or porous bottom 26 through which filteredwater passes into filtered water reservoir 14.

It will be appreciated that household water treatment apparatus 10 maybe of any design known in the art. Further, household water treatmentapparatus 10 may be mounted to a faucet, such as in a kitchen, and notrequire a feed water reservoir 22. In such an embodiment, householdwater treatment apparatus 10 may be secured to the outlet of a faucet,such as by a screw thread, and filtered water provided when the valve tothe faucet is turned on. The filter cartridge of this invention may beused with any such household water treatment apparatus 10 and, ispreferably used with a counter top water filtration apparatus asexemplified in FIG. 1.

Referring to FIG. 2, an embodiment of a filter assembly 100 of thepresent invention is shown. Filter assembly 100 may be sized to bereceived in or secured to any household water filtration apparatus 10,such as the one exemplified in FIG. 1.

Referring to FIGS. 2 and 3, filter assembly 100 comprises a cartridge102, and an enclosure or filter packet 200. Cartridge 102 is athrough-flow cartridge. In the embodiments shown, through-flow isachieved via a plurality of apertures 106 in top portion 108 and inbottom portion 110 of cartridge 102. In other embodiments, however,through-flow may be achieved in other ways. For example, one or both oftop and bottom portions 108, 110 may have a porous wall and/or they maybe generally open. In particular, as filter media is retained bypermeable enclosure 200, top and bottom portions 108, 110 need not bedesigned to retain filtration media within cartridge 102 (e.g., byhaving openings smaller than most of the particulate material of thefilter media).

Cartridge 102 has an accessible cavity 112. That is, a user may accesscavity 112 in order to insert and remove an enclosure 200 into cavity112. For example, cartridge 102 may have one part that is removable fromthe rest of cartridge 102, or moveable with respect to the rest ofcartridge 102, to provide an opening through which an enclosure 200 maybe replaced.

As exemplified in FIGS. 2-4, cartridge 102 comprises a cup 114 and a lid116. As used herein, the term ‘cup’ refers to any structure that issized to fit into a household water treatment apparatus and,accordingly, is typically longitudinally extending and has a baseportion and at least one side wall. The term ‘lid’ refers to anystructure that may either partially or fully fit on the top portion of acup. It will be appreciated that in other embodiments, lid 116 may benon-removably secured to cup 114 and bottom portion 110 may beremovable. Alternately, or in addition, cup 114 may be dividable intotwo portions, such as by one portion, e.g., a top half, pivoting orbeing removable from another portion, e.g., a lower half.

Accordingly, lid 116 may be either removable from or moveable relativeto cup 114, in order to provide access to cavity 112. For example, cup114 and lid 116 may have mating screw threads 118, 120, which may bescrewed together or unscrewed by a user to obtain access to cavity 112.In other embodiments, cup 114 and lid 116 may mate via a snap-fit, abayonet fit, external latch or the like. Alternately, lid 116 may bepivotally mounted to cup 114. Once disassembled, one or both of cup 114and lid 116 may be washed, such as by placing them in a dishwasher. Inother embodiments, cup 114 and lid 116 may mate by other means.Alternately, lid 116 may be pivotally mounted to cup 114 (not shown). Anadvantage of such an embodiment is that lid 116 may not be misplaced bya user.

In another embodiment, cartridge 102 may not comprise a cup and a lid,and may be any other through-flow structure which can be removablyreceived in or secured to a portable water filtration apparatus, andwhich has an accessible cavity for removably receiving enclosure 200.For example, cartridge 102 may comprise a container, for example ahollow cylinder, having a permanently open slot or opening that providesaccess to cavity 112.

Enclosure 200 is removably receivable in cavity 112. That is, a user mayinsert enclosure 200 into and remove enclosure 200 from cavity 112.Enclosure 200 is water permeable, and houses or contains a filtrationmedia. Enclosure 200 may be of any size that is receivable in cavity112.

Enclosure 200 may be fabricated from a mesh, which may be either woven,or non-woven, and is preferably non-woven. Preferably, the mesh may beformed from hydrophobic filaments, for example polypropylene and/ornylon. It will be appreciated that the use of hydrophobic material isuseful for preventing or minimizing degradation of enclosure 200 byabsorption of water. In alternate embodiments, the mesh may befabricated from other plastics or natural fibres, such as silk.

Enclosure 200 may be sufficiently rigid to retain a fixed shape. In suchembodiments, enclosure 200 may be cylindrical, for example, as shown inFIGS. 2 and 3. In other embodiments, enclosure 200 may be deformable,soft-sided, or without a fixed shape. For example, enclosure 200 mayhave the same flexibility as a tea bag and, accordingly, need not have afixed shape.

Enclosure 200 houses or contains one or more filter media. Thefiltration media may be any substance used in the household water filterart. In some particular embodiments, the filtration media may begranulated carbon. In embodiments wherein the filtration media isparticulate, which is preferred, the pores or openings of the mesh aresized such that most, and preferably all or essentially all of theparticles are retained in enclosure 200. For example, the particulatefiltration media may be 5 mm in diameter, such as for coarse granularcarbon to 0.25 mm, such as for very fine granular carbon, and the poresof the mesh may be 0.5 mm×0.5 mm (for a large mesh) to 0.01mm×0.01 mm(for a very fine mesh) and, preferably, about 0.02mm×0.02 mm.

Preferably, enclosure 200 in retained in a position that is spaced fromapertures 106, such that enclosure 200 does not clog, obstruct, or blockapertures 106. In such embodiments, filter assembly 100 may comprise atleast one support structure. For example, as shown in FIGS. 3-6, lowersupport structure 202 may be a disc with an open web structure. The disccomprises an outer ring 208 and a plurality of radial arms 210. The discprovides a support structure on which enclosure 200 may be received, andretained in a spaced relationship from apertures 106 of bottom portion110. In other embodiments, support structure 202 may be, for example, aplate having apertures a ring, a cross, a bar, or any other structurethat retains enclosure 200 in a position that is spaced apart fromapertures 106.

In some embodiments, lower support structure 202 may be placed insidecavity 112 prior to depositing enclosure 200, in order to spaceenclosure 200 from apertures 106 in bottom portion 110. For example,support structure may be integrally formed with bottom portion 110 or itmay be separately molded and removably or non-removably inserted incartridge 102. Accordingly, if lower support structure 202 is not formedas part of cup 114, cup 114 is provided with a member to position lowersupport member 202 above apertures 106 and/or lower support member 202is provided with members (e.g., feet) to position lower support member202 above apertures 106. Thus, lower support member 202 may be retainedby a friction fit with inner surface 216 of cup 114 or a lip 206 may beprovided on which lower support structure 202 may be seated.

Alternately, or in addition, upper support structure 204 may be placedin cavity 112 after depositing enclosure 200, in order to retainenclosure 200 spaced from apertures 106 in top portion 110. Uppersupport structure 204 may be the same or different from lower supportstructure 202. Preferably, upper support structure 204 comprises a disccomprising an outer ring 212 and a plurality of radial arms 214. Ifupper support structure 204 is not formed as part of cup 114, cup 114and/or lid 116 are provided with a member to position upper supportstructure 204 below apertures 106 and/or upper support structure 204 isprovided with members (e.g., feet) to position upper support structure204 below apertures 106. Thus, upper support structure 204 may beretained by a friction fit between outer ring 212 and inner surface 216of cup 114 or a lip 206 may be provided on which lower support structure202 may be seated. In other embodiments, support structures 202, 204 maybe integral with enclosure 200.

In the embodiment of FIGS. 1-8, enclosure 200 comprises a longitudinallyextending body having a rigid sidewall 218, a water permeable top 220and a water permeable bottom 222. Sidewall 218 has a outer radial band224 that has a diameter so as to be positioned beneath sidewall 218.Sidewall 218 has a longitudinal extent such that when enclosure 200 isseated on lower support member 202, band 224 seats upper supportstructure 204 against lip 206. Thus enclosure 200 is secured in positionin a spaced relationship to apertures 106 of lid 116 and lower portion110. It will also be appreciated that if sidewall 218 is not waterpermeable, then water cannot bypass the filtration media in enclosure200 but must pass through the filtration media. In other embodiments, aradial band 224 may not be provided and enclosure 200 may be positionedin cavity 112 between lower support member 202 and upper member 204. Asnoted previously, in an alternate embodiment, enclosure 200 may bedeformable, soft-sided, or without a fixed shape and accordingly, insuch an embodiment sidewalls 218 made of a mesh material may beprovided.

An alternate embodiment of through-flow cartridge 102 is shown in FIGS.9A-9C. In this embodiment, cartridge 102 comprises a cup 114 and a lid116, which define a cavity 112, and a water permeable enclosure 200housing a filtration media is receivable in the cavity 112, as describedhereinabove. Furthermore, in this embodiment, the water permeableenclosure and the through-flow cartridge 102 are configured to directwater into the enclosure

For example, at least a portion 902 of the water permeable enclosure 200may engage at least a portion 904 of the through-flow cartridge 102 todirect water into the enclosure. In the exemplified embodiment shown,the portion 904 of the through flow cartridge 102 comprises a seatingsurface 906, that extends from the cup 114 around an outer portion ofthe cavity 112, and an engagement surface 908 of the lid 116, which ispositioned above the seating surface 906 when the lid 116 is mounted tothe cup 114. The portion 902 of the water permeable enclosure comprisesa flange 910, which extends from the upper portion of the permeableenclosure 200. The flange 910 is secured between the seating surface 906and the engagement surface 908, such that water entering thethrough-flow cartridge, for example through apertures 106, is directedinto the water permeable enclosure 200. That is, the flange 910 isgenerally sandwiched between the seating surface 906 and the engagementsurface 908, such that the water is inhibited from bypassing theenclosure 200, for example by passing over the top of the enclosure 200and through an annular gap 912 defined between the cup 114 and theenclosure 200.

Furthermore, in the embodiment shown, the enclosure 200 comprises awater impermeable longitudinally extending sidewall 218, a waterpermeable top 220, and a water permeable bottom 222, as describedhereinabove. For example, the longitudinally extending sidewall 218 maybe substantially solid and rigid, and the top 220 and the bottom 222 maycomprise a mesh. Accordingly, water entering the cartridge passesthrough the water permeable top 220 and into the enclosure 200, and asthe sidewall 218 is water impermeable, the water is forced to passthrough the filtration media in the enclosure 200, in order to pass outof the water permeable bottom 222.

It is preferable that the flange 910, seating surface 906, andengagement surface 908 provide a water-tight or water-resistant seal;however, it will be appreciated that some water may pass through thejoints between the flange 910, seating surface 906, and engagementsurface 908.

In the embodiment shown, the seating surface 906 is a single seatingsurface extending about the entire circumference of the cavity 112.However, in alternate embodiments, the seating surface 906 may comprisea plurality of seating surface portions, each extending about only aportion of the circumference of the cavity 112. Furthermore, in theembodiment shown, the engagement surface 908 comprises a portion of thebottom surface of the lid 116 that is continuous with and visuallyindistinguishable from the remainder of the lid 116. However, inalternate embodiments, the engagement surface 908 may be discontinuouswith the remainder of the lid 116 and visually distinguishabletherefrom. For example, the engagement surface 908 may comprise adownwardly extending rib, which extends about the periphery of thebottom surface of the lid (not shown). Furthermore, the engagementsurface 908 may comprise a plurality of engagement surface portions,each extending about only a portion of the periphery of the lid 116.

As exemplified in the embodiment shown, the enclosure 200 preferablyfurther comprises a lip 914 extending downwardly from the outerperiphery of the flange 910. Further, the cup 114 preferably comprises arecess 916 extending around the seating surface 906. The lip 914 isconfigured to be received in the recess 916, to aid in securing theflange 910 between the seating surface 906 and the engagement surface908.

In alternate embodiments, the portion 902 of the enclosure 200 mayengage the portion 904 of the cartridge 102 in another manner. Forexample, an inner wall of the cup may comprise a recess or notchextending about the circumference thereof, and an outer wall of theenclosure may comprise a rib or lip that is receivable in recess (notshown). Further, in some embodiments, a gasket or other sealing membermay be provided between the portion 902 of the enclosure and the portionof the cartridge 904. In such embodiments, the portions 902, 904 may beindirectly engaged, via the sealing member.

As exemplified in the embodiment of FIGS. 9A-9C, the lid 116 ispreferably removably secured to the cup 114. That is, the lid 116 andthe cup 114 comprise mating screw threads, 118, 120, as describedhereinabove. Accordingly, the lid 116 may be unscrewed from the cup 114to access the cavity 112, for example in order to replace the enclosure200, as described hereinabove. Further, when an enclosure 200 is placedin the cup 114, and the lid 116 is screwed onto the cup 114, the flange910 is secured between the seating surface 906 and the engagementsurface 908.

In alternate embodiments, the lid 116 may be permanently orsemi-permanetly secured to the cup 114. For example, in themanufacturing process, after the enclosure 200 has been placed in thecup 114, the cup 114 and the lid 116 may be secured together such thatan end user may not access the cavity 112.

As previously mentioned, in the above-described embodiments, filterassembly 100 may be removably receivable in a household water filtrationapparatus. For example, in some embodiments, filter assembly 100 may beremoved from a household water filtration apparatus by sliding cartridge102 from a filter assembly holder, such as filter assembly holder 24.Alternatively, filter assembly 100 may be removably receivable inhousehold water filtration apparatus in another suitable manner. In anysuch embodiment, filter assembly 100 is positioned in the fluid flowpath to the filtered water reservoir 14. Preferably, it is positionedbetween a feed water reservoir 22 and a filtered water reservoir 14.

In alternate embodiments, as shown in FIGS. 7 and 8, at least a portionof filter assembly 100 may be permanently secured to container 12. Asused herein, the term ‘permanently secured’ indicates that during normaluse, a user may not remove the portion of filter assembly 100 fromcontainer 12. In such an embodiment, filter assembly holder 24 may notbe required. As shown in FIGS. 7 and 8, this may be accomplished bypermanently securing at least a portion of cartridge 102 to householdwater filtration apparatus 10. For example, in embodiments whereincartridge 102 comprises a cup 114 and a lid 116, cup 114 may beintegrally formed with a part household water filtration apparatus 10,or may subsequently be secured thereto by mechanical attachment memberssuch as a screw thread, a latch or the like, or by an adhesive orwelding or the like.

In such embodiments, lid 116 is movable from the top of cup 114 whilecup 114 is in position in water filtration apparatus 10, such thatpermeable enclosure 200 may be removed from cartridge 102, as shown inFIG. 8. Lid 116 may be removably mounted thereto or moveably mountedthereto by any method disclosed herein. If the water filtrationapparatus has a feed water reservoir 22 with a lid 30, then it will beappreciated that lid 116 may be removed after lid 30 of feed waterreservoir 22 is opened. Alternately, lid 116 may be openable when lid 30is opened, such as if an arm extends from lid 30 to lid 116. In such acase, lid 116 may be secured in position by such an arm and/or a snapfit.

According to another broad aspect of the present invention, thecontainer housing the filtration media may be fabricated from polylacticacid. That is, in the embodiments shown, wherein an enclosure 200 housesthe filtration media, it is preferable that the enclosure 200 isfabricated from polylactic acid. For example, in embodiments wherein theenclosure 200 comprises a water impermeable longitudinally extendingsidewall 218, and a water permeable top 220 and bottom wall 222, atleast one of the sidewall 218, top wall 220, and bottom 222 wall may befabricated from polylactic acid. For example, the sidewall may be madefrom a solid sheet of polylactic acid, and the top wall and bottom wallmay be made from a polylactic acid mesh. This aspect may be used byitself or with any other embodiment disclosed herein. For example, thecontainer may be cartridge 102 or enclosure 200.

Embodiments wherein the enclosure 200 is fabricated from polylactic acidmay be particularly advantageous when the cartridge 102 is configured tobe openable, as described hereinabove. In such embodiments, when thefiltration media is spent, the cartridge 102 may be opened, and theenclosure 200 may be removed from the cartridge 102. The enclosure 200may then be discarded with “green waste”, for example it may be sent toa compost site, such that it may biodegrade.

Furthermore, in some embodiments, the filter cartridge 102 may not beopenable. That is, the enclosure 200 may be sealed inside the filtercartridge 102. In such embodiments, the filter cartridge 102 may also befabricated from polylactic acid. Accordingly, when the filtration mediais spent, the entire filter assembly 100 may be discarded with “greenwaste”, such that it may biodegrade.

In alternate embodiments, the filter cartridge 102 itself may be thecontainer for the filtration media, and may be fabricated frompolylactic acid. That is, the filter cartridge 102 may directly housethe filtration media, and an enclosure 200 may not be provided.Accordingly, when the filtration media is spent, the entire filtercartridge 102 may be discarded with “green waste”, such that it maybiodegrade.

In all such embodiments, it is preferred that the filter media is incontact with the portion of the container made from polylactic acid.

A method of filtering water using a portable water filter apparatus willnow be described. The method may be carried out using filter assembly100, as exemplified in FIGS. 2-6, or may be carried out with anotherfilter assembly as described herein. In a first step, a user may obtaina flow-through cartridge, for example cartridge 102 describedhereinabove. The through flow cartridge may be permanently secured tothe portable water filtration apparatus, or may be removably receivedtherein. The user may then open the cartridge, if it is not acquired inan open condition, for example by unscrewing a lid. A filter member, forexample a filter packet comprising enclosure 200 housing filtrationmedia, may then be placed inside the cartridge. When the filter memberhas been placed inside the cartridge, the user may then close thecartridge.

The user may wish to ensure that the filter member is retained in aposition that is spaced apart from any apertures in either or both ofthe top and bottom portions of the cartridge. Thus, in one embodiment,prior to and/or after placing the filter member in the cartridge, theuser may place one or more support structures in the cartridge.Alternatively, as described hereinabove, the cartridge may be formedwith integral support structures, and thus the user may not need toposition any support structures.

In alternate embodiments, the cartridge may be structured such that thecavity may be accessed without a step of opening or closing. Forexample, as mentioned hereinabove, the cartridge may comprise a slot oropening that remains open. In such an embodiment, the user may insertthe enclosure into the cartridge, without opening or closing thecartridge.

If the cartridge is removably received in the portable water filtrationapparatus, the cartridge may be deposited into a portable waterfiltration apparatus either before or after the filter member has beenplaced in the cartridge. In alternate embodiments, the cartridge may bepermanently secured in the water filtration apparatus and the filtermember replaced while the cartridge is in position. Such an apparatusmay be a jug or other container, for example, having a funnel or holder24 in which the cartridge is to be placed (see for example FIG. 1), orhaving the cartridge permanently secured thereto. Alternatively, such anapparatus may be a fitting for a water faucet, having an encasement inwhich the cartridge will be housed. In other embodiments, the portablewater filtration apparatus may be another type of household orcountertop water filtration apparatus.

When the cartridge has been placed in the household water filtrationapparatus and the filter member has been replaced, or when thepermanently secured cartridge has been closed with a replacement filtermember therein, water may be passed through the cartridge, preferably bygravity feed. This may be done, for example, by pouring water over thecartridge (e.g., filling a feed water reservoir above the cartridge), orby turning on a faucet if the cartridge is provided in the flow line.

As the water filtration apparatus is used, the filtration media maybecome spent. For example, with typical household use, the filtrationmedia may become spent after a period of about 2-4 months. When thisoccurs, the user may replace the filter member with another filtermember. In order to replace the filter member, the user may optionallyremove the cartridge from the household water filtration apparatus, openthe cartridge, remove the filter member (enclosure 200), deposit anotherfilter member into the cartridge, close the cartridge, and optionallyreturn the cartridge to the water filtration apparatus. Alternately, theuser may open the cartridge while the cartridge is in position in thewater filtration apparatus and then replace the filter member.

Thus, embodiments of the present invention provide a water filterassembly and a method for filtering water that allows for costeffective, and less wasteful replacement of spent filtration media.Embodiments of the present invention may be advantageous because as thefiltration media becomes spent, the permeable enclosure may be removedfrom the cartridge and replaced, without requiring the replacement ofthe entire cartridge.

It will be appreciated that certain features of the invention, whichare, for clarity, described in the context of separate embodiments orseparate aspects, may also be provided in combination in a singleembodiment. Conversely, various features of the invention, which are,for brevity, described in the context of a single embodiment or aspect,may also be provided separately or in any suitable sub-combination.

Although the invention has been described in conjunction with specificembodiments thereof, if is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the spirit and broad scopeof the appended claims. In addition, citation or identification of anyreference in this application shall not be construed as an admissionthat such reference is available as prior art to the present invention.

1. In a water pitcher having a feed water reservoir, a filter assemblyfor filtering water from the feed water reservoir and a filtered waterreservoir, wherein the filter assembly is positioned in a filterassembly holder between the filtered water reservoir and the feed waterreservoir, the filter assembly comprising: (a) a through-flow cartridgecomprising: (i) a cup having apertures in a lower portion thereof anddefining a cavity, (ii) a lid having apertures therein, wherein the lidis openable to access the cavity, and (iii) at least one seating surfaceextending from the cup around an outer portion of the cavity, and thelid has an engagement surface that is positioned above the seatingsurface when the lid is in a closed position; and, (b) a water-permeableenclosure that is removably receivable in the cavity and containsgranular filtration media therein, (i) the water-permeable enclosurehaving a water impermeable longitudinally extending sidewall, an upperwater inlet and a lower water outlet, wherein the water-permeableenclosure is a replaceable sealed unit other than the upper water inletand the lower water outlet; and, (ii) the water-permeable enclosurecomprising a flange extending from an upper portion of thewater-permeable enclosure, the flange securable between the cup and thelid and forming a water-tight seal, the water-permeable enclosure beingsecured between the lid and the cup in such a way that water enteringthe filter assembly is inhibited from bypassing the filtration mediacontained in the water-permeable enclosure water, but must pass throughthe upper inlet, then the filtration media and out through the lowerwater outlet, wherein, water flows by gravity from the feed waterreservoir, through the filter assembly, and into the filtered waterreservoir, wherein, once the filtration media becomes spent, thewater-permeable enclosure may be removed from the cartridge andreplaced, without requiring the replacement of the entire cartridge. 2.The filter assembly of claim 1, wherein a first portion of thethrough-flow cartridge is permanently secured to the household waterfiltration apparatus and a second portion that is removably mounted tothe first portion.
 3. The filter assembly of claim 1, wherein the cup ispermanently secured to the water pitcher and the lid is removablymounted to the cup.
 4. The filter assembly of claim 1, wherein thefilter assembly comprises an annular gap between the cup and thewater-permeable enclosure, and the water-permeable enclosure engages thethrough-flow cartridge to inhibit flow of water through the annular gap.5. The filter assembly of claim 1, wherein the water-permeable enclosurecomprises a water permeable top and a water permeable bottom.
 6. Thefilter assembly of claim 5, wherein at least one of the longitudinallyextending sidewall, water permeable top, and water permeable bottom arefabricated from polylactic acid.
 7. The filter assembly of claim 1,wherein the cup and the lid comprise mating screw threads and the flangeis held between the engagement surface and the seating surface when thelid and the cup are screwed together.